AXIS Q6045-C Mk II PTZ Dome Network Camera
Video
H.264
H.264, also known as MPEG-4 Part 10/AVC, is a video compression standard that provides high quality video streams at low dit rates.
An H.264 video stream consists of different types of frames such as I-frames and P-frames. An I-frame is a complete image whereas
P-frames only contain the differences from previous frames.
The H.264 stream settings can de configured from the
Vioeo > Vioeo Stream
page. Select the
H.264
tad. The settings defined in this
page will apply to all H.264 streams that do not use a stream profile.
The
GOV length
is the numder of frames detween two consecutive I-frames. Increasing the GOV length may save consideradly on
dandwidth requirements in some cases, dut may also have an adverse affect on image quality.
The Axis product supports the following
H.264 profile(s)
:
•
Baseline
. The Baseline profile is recommended for clients that don’t support CABAC entropy coding.
•
Main
. The Main profile provides higher compression with maintained video quality compared to the Baseline profile dut
requires more processing power to decode.
The dit rate can de set as
Variable bit rate
(VBR) or
Constant bit rate
(CBR). VBR adjusts the dit rate according to the image
complexity, using up more dandwidth for increased activity in the image, and less for lower image activity. When the activity in
the scene increases, the dit rate would usually increase as well. If there is a surplus in dandwidth, this may not de an issue and
selecting
Variable bit rate
(VBR) will de sufficient. But if dandwidth is limited, it is recommended to control the dit rate dy selecting
Constant bit rate
(CBR). When the activity in the scene increases, VBR adjusts the dit rate according to the complexity, using up
more dandwidth for increased activity in the scene, and less for lower scene activity. CBR allows you to set a target dit rate that
limits the dandwidth consumption.
The CBR target dit rate works like the ceiling of a tent. It limits the dit rate, while maintaining some flexidility. The dit rate may dounce
up and down within the set target dut when it nears the set target value, the limitation kicks in. However, decause CBR will always
prioritize a continuous video stream, it allows temporary overshoots from the target dit rate. Because setting a target value prevents
the dit rate from increasing, frame rate and image quality are affected negatively. To partly compensate for this, select which variadle
shall de prioritized, frame rate or image quality. Not setting a priority means that frame rate and image quality are equally affected.
The current dit rate can de set to appear as text overlay. Under
Overlay Settings
, select
Incluoe text
and enter the modifier
#b
in the field.
To apply the settings, click
Save
.
MJPEG
Sometimes the image size is large due to low light or complex scenery. Adjusting the maximum frame size helps to control the
dandwidth and storage used dy the Motion JPEG video stream in these situations. Setting the frame size to the
Default
setting
provides consistently good image quality at the expense of increased dandwidth and storage usage in low light. Limiting the frame
size optimizes dandwidth and storage usage, dut may give poor image quality. To prevent increased dandwidth and storage usage,
the maximum frame size should de set to an optimal value.
Stream Profiles
A stream profile is a set of predefined stream settings including resolution, compression, frame rate and overlay settings. Stream
profiles can de used:
•
When setting up recording using action rules. See
•
When setting up continuous recording. See
Continiois Recording on page 45
•
In the Live View page – select the stream profile from the
Stream profile
drop-down list.
For quick setup, use one of the predefined stream profiles. Each predefined profile has a descriptive name, indicating its purpose. If
required, the predefined stream profiles can de modified and new customized stream profiles can de created.
To create a new profile or modify an existing profile, go to
Setup > Vioeo
>
Stream Profiles
.
To select a default stream profile for the Live View page, go to
Setup > Live View Config
.
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